Achiria

Achiria
Achiria
	Patients with Achiria have an impaired sense of touch
Specialty	Neurology
Symptoms	Inability to recognize or perceive one side of the body.
Types	Sensory Achiria, Motor Achiria, and Introspective Achiria.

Last updated May 06, 2024

Achiria, also referred to as "Simple Allochiria", is a neurological disorder in which a patient is unable to recognise or perceive one side of their body.^[1] It is oftentimes associated with dyschiria, also known as a form of unilateral neglect or hemispatial neglect. The term achiria is seldom used in modern scientific literature.

Patients with achiria would have deficits in sensory, motor and introspective areas of consciousness. The symptoms are associated with hysteria, spinal lesions and unilateral neglect syndrome. In Greek terminology, "chiria" or "χεiρ" means hand, while the "a-" prefix means "without" or "not".^[3]^[4] However, in actual clinical practice, achiria is also referred to the inability to localize stimuli from other parts of the body.

Types

There are three manifestations of achiria, though the majority of cases focus on the sensory aspect.^{[ citation needed ]}

Sensory achiria

Sensory achiria describes the situation when the patient is not able to feel the sidedness of a stimulus when it is applied to a body part. According to Welsh psychiatrist Ernest Jones, patients with sensory achiria are certain that they do not know which side of the body the stimulus comes from, instead of being uncertain and struggling between picking a side.^[1]

Despite the spatial disorder, the patient's sensory acuity is not necessarily affected. He/she might be able to effectively tell the position, intensity and nature of the stimulus applied, with the exception of the side of the body of which it is applied. Allochiria is the modern term that covers this phenomenon.^[5]

Motor achiria

Motor achiria describes the situation when the patient is not able to move the limb or body part in question without assistance due to the inability to distinguish left and right limbs. Voluntary movement is possible when cues other than left or right are given to the patient, but the movement is of a disproportionate strength.^[1]

However, it is also reported that involuntary movements or habitual movements do occur in the limb in question. Similar to other disorders related to hysteria, the movement of limbs is more impaired as the movement itself is more under conscious control.^[2] The modern term with approximately the same meaning is motor neglect, where the patients rarely use their contralateral limbs.

Introspective achiria

Introspective achiria describes the situation when the patient is not able to feel or retain sensory memory of the body part in question. Even when the patient knows that that body part exists on their body, they still could not feel it.^[1]

History

Discovery

The first reported case of achiria was discovered in 1899 by Pierre Janet, a pioneering French psychologist. Janet noticed that a patient had an unusual symptom, of which he was not able to localize physical touch on his body. Janet named the phenomenon "simple allochiria".^[6]

The term "achiria" was first coined by Welsh psychiatrist Ernest Jones in 1907.^[7] After reviewing the past literature on allochiria from Janet, Austrian neurologist Heinrich Obersteiner and other psychologists, Jones redefined the term allochiria into two separate terms: "True allochiria" and "False allochiria" (also known as alloesthesia). False allochiria is the mislocalization of stimuli in all directions, while true allochiria is the mislocalization of stimuli only in the horizontal direction to the exact same location of the contralateral side of the body. When being touched at the inner ankle, patients with false allochiria could feel the sensation at the outer ankle, the knee, or the opposite ankle; while patients with true allochiria could only feel it at the exact same location of the inner ankle of the opposite limb. Furthermore, Jones proposed that true allochiria would be one of the three stages of a mental syndrome called dyschiria, alongside achiria and synchiria, hence the term "achiria" is coined.^[7]

Achiria often refers to the complete absence of chirognostic sense, or the sense of "sidedness" on the body. Therefore, a patient with achiria would be able to accurately tell the position and intensity of stimuli, but was unable to identify which side of the body the stimuli originated from.^[2]

Theory

There are a number of different approaches that explain the origin and symptoms of achiria.

Hammond's theory

The first theory was proposed by William A. Hammond in 1883. This theory posits that achiria (the term was not officially coined at the time) is caused by an obstruction in the efferent path, which results in impulses being passed to the contralateral side of the body, hence reaching the cerebral hemisphere opposite to where the impulses originated from.^[8]

In 1891, Albert Paul Weiss tried to validate this theory by blocking the posterior columns of the spinal cord.^[9] Bosc also did a similar demonstration in 1892, but he blocked one side of the cerebral hemisphere instead of the spinal cord, such that the signals trying to get to that hemisphere have to pass through the corpus callosum to the opposite hemisphere instead of other pathways.^[10]

Jones' theory

The second theory was proposed by Ernest Jones in 1909.^[2] Jones argued that Hammond's theory was merely a speculation because it ignored observable facts about achiria and allochiria, such as their associations with Brown-Sequard hemisection syndrome. Brown-Sequard hemisection syndrome features a unilateral block in the spinal cord, but allochiria has been recorded in patients with this syndrome. This contradicted what Hammond's theory suggests.^[2]

Jones posits that achiria is a dissociation disorder resulting from the loss of the chirognostic sense, or the sensation of "sidedness". Chirognostic sense is a type of autosomastognostic sense, or "memory senses", which we acquire through our memories of the past; as opposed to the aesthesic senses, which are senses we acquire at any given moment and through our immediate interaction with the outside world, such as heat, touch and pain, etc.^[2]

He further elaborated that functional diseases could cause damage to both types of senses. During the recovery of the functional disease, aesthesic senses may recover faster than the autosomatognostic senses, resulting in a gap between the recovery pace of different senses. This gap is called "paradoxical cleavage". Thus, a patient could accurately detect touch and pain, but is not able to recall the sidedness of this sensation. The larger the paradoxical cleavage, the more severe the symptoms would be.^[2]

Achiria and allochiria

Jones regarded achiria as the primary stage of dyschiria, of which the patients have a complete loss of their chirognostic senses. When they slowly regain back their chirognostic senses, the symptoms of achiria would transit to those of allochiria.^[2] The theory behind this change is as follows:

When a patient transits from achiria to allochiria, there is a gain in both motor function (the patient would be able to move their limbs in both sides of the body, instead of just one) as well as a gain in chirognostic memories, albeit them being distorted and the memory of one side is recalled as those of the opposite side.^[2]

The improvement of motor function and the redemption of memory senses, which were absent or incomplete in achiria patients, enhances their general well-being and their feelings of strength, power and completeness. Therefore, allochiria should be seen as a more stable and improved status than achiria, while achiria should be seen as a transitional stage. This theory was supported by the comparative prevalence of achiria and allochiria. Out of the thirty cases that Jones had collected from past literature, allochiria was present in all cases, while achiria was only present in one.^[2]

Unilateral neglect

The previous experiments related to dyschiria were not enough to make a theoretical influence.^[11] The term dyschiria was replaced by the term unilateral neglect in 1970 when Austrian neurologist Marcel Kinsbourne published a study called "A Model for the Mechanism of Unilateral Neglect of Space".^[12] In the study, Kinsbourne briefly mentioned the lack of awareness to the contralateral side to the brain lesion. Since there had already been previous studies related to unilateral neglect, this term was used instead of dyschiria. In fact, studies about unilateral neglect had started in the late 19th century, but not until a century later that it became a major topic in neurology.^[13] However, previous studies mainly focused on other aspects of unilateral neglect, like the visual aspect. For visual neglect, patients would ignore one side of their visual field.^[14]

Related Research Articles

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<span class="mw-page-title-main">Myoclonus</span> Involuntary, irregular muscle twitch

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<span class="mw-page-title-main">Hemispatial neglect</span> Medical condition

Hemispatial neglect is a neuropsychological condition in which, after damage to one hemisphere of the brain, a deficit in attention and awareness towards the side of space opposite brain damage is observed. It is defined by the inability of a person to process and perceive stimuli towards the contralesional side of the body or environment. Hemispatial neglect is very commonly contralateral to the damaged hemisphere, but instances of ipsilesional neglect have been reported.

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<span class="mw-page-title-main">Foix–Chavany–Marie syndrome</span> Medical condition

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A somatosensory disorder is an impairment of the somatosensory system.

Extinction is a neurological disorder that impairs the ability to perceive multiple stimuli of the same type simultaneously. Extinction is usually caused by damage resulting in lesions on one side of the brain. Those who are affected by extinction have a lack of awareness in the contralesional side of space and a loss of exploratory search and other actions normally directed toward that side.

<span class="mw-page-title-main">Allochiria</span> Medical condition

Allochiria is a neurological disorder in which the patient responds to stimuli presented to one side of their body as if the stimuli had been presented at the opposite side. It is associated with spatial transpositions, usually symmetrical, of stimuli from one side of the body to the opposite one. Thus a touch to the left side of the body will be reported as a touch to the right side, which is also known as somatosensory allochiria. If the auditory or visual senses are affected, sounds will be reported as being heard on the opposite side to that on which they occur and objects presented visually will be reported as having been presented on the opposite side. Often patients may express allochiria in their drawing while copying an image. Allochiria often co-occurs with unilateral neglect and, like hemispatial neglect, the disorder arises commonly from damage to the right parietal lobe.

Amorphosynthesis, also called a hemi-sensory deficit, is a neuropsychological condition in which a patient experiences unilateral inattention to sensory input. This phenomenon is frequently associated with damage to the right cerebral hemisphere resulting in severe sensory deficits that are observed on the contralesional (left) side of the body. A right-sided deficit is less commonly observed and the effects are reported to be temporary and minor. Evidence suggests that the right cerebral hemisphere has a dominant role in attention and awareness to somatic sensations through ipsilateral and contralateral stimulation. In contrast, the left cerebral hemisphere is activated only by contralateral stimuli. Thus, the left and right cerebral hemispheres exhibit redundant processing to the right-side of the body and a lesion to the left cerebral hemisphere can be compensated by the ipsiversive processes of the right cerebral hemisphere. For this reason, right-sided amorphosynthesis is less often observed and is generally associated with bilateral lesions.

Somatosensory evoked potential is the electrical activity of the brain that results from the stimulation of touch. SEP tests measure that activity and are a useful, noninvasive means of assessing somatosensory system functioning. By combining SEP recordings at different levels of the somatosensory pathways, it is possible to assess the transmission of the afferent volley from the periphery up to the cortex. SEP components include a series of positive and negative deflections that can be elicited by virtually any sensory stimuli. For example, SEPs can be obtained in response to a brief mechanical impact on the fingertip or to air puffs. However, SEPs are most commonly elicited by bipolar transcutaneous electrical stimulation applied on the skin over the trajectory of peripheral nerves of the upper limb or lower limb, and then recorded from the scalp. In general, somatosensory stimuli evoke early cortical components, generated in the contralateral primary somatosensory cortex (S1), related to the processing of the physical stimulus attributes. About 100 ms after stimulus application, additional cortical regions are activated, such as the secondary somatosensory cortex (S2), and the posterior parietal and frontal cortices, marked by a parietal P100 and bilateral frontal N140. SEPs are routinely used in neurology today to confirm and localize sensory abnormalities, to identify silent lesions and to monitor changes during surgical procedures.

Alternating hemiplegia is a form of hemiplegia that has an ipsilateral cranial nerve palsies and contralateral hemiplegia or hemiparesis of extremities of the body. The disorder is characterized by recurrent episodes of paralysis on one side of the body. There are multiple forms of alternating hemiplegia, Weber's syndrome, middle alternating hemiplegia, and inferior alternating hemiplegia. This type of syndrome can result from a unilateral lesion in the brainstem affecting both upper motor neurons and lower motor neurons. The muscles that would receive signals from these damaged upper motor neurons result in spastic paralysis. With a lesion in the brainstem, this affects the majority of limb and trunk muscles on the contralateral side due to the upper motor neurons decussation after the brainstem. The cranial nerves and cranial nerve nuclei are also located in the brainstem making them susceptible to damage from a brainstem lesion. Cranial nerves III (Oculomotor), VI (Abducens), and XII (Hypoglossal) are most often associated with this syndrome given their close proximity with the pyramidal tract, the location which upper motor neurons are in on their way to the spinal cord. Damages to these structures produce the ipsilateral presentation of paralysis or palsy due to the lack of cranial nerve decussation before innervating their target muscles. The paralysis may be brief or it may last for several days, many times the episodes will resolve after sleep. Some common symptoms of alternating hemiplegia are mental impairment, gait and balance difficulties, excessive sweating and changes in body temperature.

Tactile hallucination is the false perception of tactile sensory input that creates a hallucinatory sensation of physical contact with an imaginary object. It is caused by the faulty integration of the tactile sensory neural signals generated in the spinal cord and the thalamus and sent to the primary somatosensory cortex (SI) and secondary somatosensory cortex (SII). Tactile hallucinations are recurrent symptoms of neurological diseases such as schizophrenia, Parkinson's disease, Ekbom's syndrome and delirium tremens. Patients who experience phantom limb pains also experience a type of tactile hallucination. Tactile hallucinations are also caused by drugs such as cocaine and alcohol.

Dyschiria, also known as dyschiric syndrome, is a neurological disorder where one-half of an individual's body or space cannot be recognized or respond to sensations. The term dyschiria is rarely used in modern scientific research and literature. Dyschiria has been often referred to as unilateral neglect, visuo-spatial neglect, or hemispatial neglect from the 20th century onwards. Psychologists formerly characterized dyschiric patients to be unable to discriminate or report external stimuli. This left the patients incapable of orienting sensory responses in their extrapersonal and personal space. Patients with dyschiria are unable to distinguish one side of their body in general, or specific segments of the body. There are three stages to dyschiria: achiria, allochiria, and synchiria, in which manifestations of dyschiria evolve in varying degrees.

References

1 2 3 4 5 JONES, ERNEST (1908). "The Precise Diagnostic Value of Allochiria". Brain. 30 (4): 490–532. doi:10.1093/brain/30.4.490.
1 2 3 4 5 6 7 8 9 10 Jones, Ernest (1909). "The Dyschiric syndrome". The Journal of Abnormal Psychology. 4 (5): 311–327. doi:10.1037/h0075421.
↑ Berti, Anna (1 January 2004). "Cognition in Dyschiria: Edoardo Bisiach's Theory of Spatial Disorders and Consciousness". Cortex. 40 (2): 275–280. doi:10.1016/S0010-9452(08)70122-9. ISSN 0010-9452. PMID 15156785. S2CID 4478844.
↑ "Definition of a- | Dictionary.com". www.dictionary.com. Retrieved 2020-04-27.
↑ Li, Korina; Malhotra, Paresh A (2015-05-28). "Spatial neglect". Practical Neurology. 15 (5): 333–339. doi:10.1136/practneurol-2015-001115. ISSN 1474-7758. PMC 4602245 . PMID 26023203.
↑ Dumas, G. (1899). Revue Philosophique de la France et de l'Étranger. Presses Universitaires de France. pp. 646–668.
1 2 Jones, Ernest (September 1907). "The Clinical Significance of Allochiria". The Lancet. 170 (4386): 830–832. doi:10.1016/s0140-6736(00)50066-x. ISSN 0140-6736.
↑ Hammond, William A. (1883). "Allochiria: Its Nature and Seat". New York Medical Journal. 37: 35–37.
↑ Weiss, Albert P. (1891-11-22). "Uber anderseitige Emfindungswahrnehmungen und anderseitige Bewegungserscheinungen". Wien. Med. Presse. 32: 1779.
↑ Bosc (1892). "De l'allochirie sensorielle". Rev. De Med. 12: 841.
↑ Bisiach, Edoardo; Berti, Anna (1987), "Dyschiria. An Attempt at its Systemic Explanation", Advances in Psychology, Elsevier, pp. 183–201, doi:10.1016/s0166-4115(08)61713-6, ISBN 978-0-444-70193-0
↑ Kinsbourne, Marcel (1970-07-20). "A model for the mechanism of unilateral neglect of space". Transactions of the American Neurological Association. 95: 143–6. PMID 5514359.
↑ Bisiach, Edoardo (2020-03-06), "Unilateral Neglect and Related Disorders", Handbook of Clinical and Experimental Neuropsychology, Psychology Press, pp. 479–496, doi:10.4324/9781315791272-27, ISBN 978-1-315-79127-2, S2CID 216162586
↑ Bartolomeo, Paolo (2007). "Visual neglect" (PDF). Current Opinion in Neurology. 20 (4): 381–386. doi:10.1097/WCO.0b013e32816aa3a3. ISSN 1350-7540. PMID 17620870. S2CID 18332604.

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[:0-1] 1 2 3 4 5 JONES, ERNEST (1908). "The Precise Diagnostic Value of Allochiria". Brain. 30 (4): 490–532. doi:10.1093/brain/30.4.490.

[:1-2] 1 2 3 4 5 6 7 8 9 10 Jones, Ernest (1909). "The Dyschiric syndrome". The Journal of Abnormal Psychology. 4 (5): 311–327. doi:10.1037/h0075421.

[:2-3] Berti, Anna (1 January 2004). "Cognition in Dyschiria: Edoardo Bisiach's Theory of Spatial Disorders and Consciousness". Cortex. 40 (2): 275–280. doi:10.1016/S0010-9452(08)70122-9. ISSN 0010-9452. PMID 15156785. S2CID 4478844.

[4] "Definition of a- | Dictionary.com". www.dictionary.com. Retrieved 2020-04-27.

[5] Li, Korina; Malhotra, Paresh A (2015-05-28). "Spatial neglect". Practical Neurology. 15 (5): 333–339. doi:10.1136/practneurol-2015-001115. ISSN 1474-7758. PMC 4602245 . PMID 26023203.

[6] Dumas, G. (1899). Revue Philosophique de la France et de l'Étranger. Presses Universitaires de France. pp. 646–668.

[:3-7] 1 2 Jones, Ernest (September 1907). "The Clinical Significance of Allochiria". The Lancet. 170 (4386): 830–832. doi:10.1016/s0140-6736(00)50066-x. ISSN 0140-6736.

[8] Hammond, William A. (1883). "Allochiria: Its Nature and Seat". New York Medical Journal. 37: 35–37.

[9] Weiss, Albert P. (1891-11-22). "Uber anderseitige Emfindungswahrnehmungen und anderseitige Bewegungserscheinungen". Wien. Med. Presse. 32: 1779.

[10] Bosc (1892). "De l'allochirie sensorielle". Rev. De Med. 12: 841.

[11] Bisiach, Edoardo; Berti, Anna (1987), "Dyschiria. An Attempt at its Systemic Explanation", Advances in Psychology, Elsevier, pp. 183–201, doi:10.1016/s0166-4115(08)61713-6, ISBN 978-0-444-70193-0

[12] Kinsbourne, Marcel (1970-07-20). "A model for the mechanism of unilateral neglect of space". Transactions of the American Neurological Association. 95: 143–6. PMID 5514359.

[13] Bisiach, Edoardo (2020-03-06), "Unilateral Neglect and Related Disorders", Handbook of Clinical and Experimental Neuropsychology, Psychology Press, pp. 479–496, doi:10.4324/9781315791272-27, ISBN 978-1-315-79127-2, S2CID 216162586

[14] Bartolomeo, Paolo (2007). "Visual neglect" (PDF). Current Opinion in Neurology. 20 (4): 381–386. doi:10.1097/WCO.0b013e32816aa3a3. ISSN 1350-7540. PMID 17620870. S2CID 18332604.

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